Liquid detergents are known from the state of the art. Such detergents are, for example, described in U.S. Pat. No. 5,880,083, WO 2004/065535 A1, and WO 2004/041990 A1. One problem in the formulation of liquid detergent is to develop formulations that can be judged satisfactory regarding the performance perspective, that is to remove the dirt without damaging tissue while the fabrics to impart a pleasant softness and to reduce the electrostatic charge between the fibers. On the other hand the emulsions need to be sufficiently viscous and stable on storage, so that even under temperature stress over several months, neither the viscosity collapses nor phase separation occurs.
The document WO 2007/101470 describes a liquid detergent composition which is storage-stable and shows a good washing performance. As non-ionic surfactants linear alkoxylated alcohols are used in the detergent composition. These are, for example, linear fatty alcohol ethoxylates having a C13-C15 alkyl group and 7 EO units. These liquid detergent concentrate compositions according to the state of art comprised about 1-70 wt.-% of said alkoxylated fatty alcohol. These liquid detergent compositions contain solubilizers which are able to keep the components in solution and the resulting emulsion stable even over a longer storage time. This was achieved by the use of one or more cross-linked or partly cross-linked polyacrylic acids and/or polymethacrylic acids in the composition.
These substances are used as thickener and stabiliser for a liquid detergent concentrate composition which represent an emulsion. These polyacrylic acid or polymethacrylic acid may be cross-linked or partly cross-linked with a polyalkenyl polyether compound as crosslinker. Those compounds are available under the trade name Carbopol® from Noveon.
The drawback of the prior art compositions is the production process to introduce the cross-linked or partly cross-linked polyacrylic acid/polymethacrylic acid thickener and stabilisers into the emulsion. The production process of the emulsions of the state of art requires the use of a premix to introduce the thickening polymer, i.e. the solid cross-linked or partly cross-linked polyacrylic acid/polymethacrylic acid, into the formula. This premix is both expensive and time-consuming due to the nature of the addition, which also involves a milling step. Within the premix, a powder eductor recirculates a liquid surfactant to which the powder polymer is added. This premix is then added to the rest of the emulsion. Therefore it was the aim of the present invention to replace this stabilizing system with one that is easier to handle.